25 hp merc power problem

M

mjf

Recruit
Joined
May 11, 2003
Messages
2
I have a 1989 25 hp. merc. that I purchased new. It has been a great motor, never had a problem. Last season I started to develop one. When I put boat in water, it starts on first or second pull (always did)when I put it in gear motor runs about 1/4 speed for 5 or 10 minutes. During this time motor sometimes sounds like its trying to "kick in". It finally will "kick in" and motor will run fine for rest of day. This does not happen all the time, but most of the time. I've replaced the plugs, fuel filter, gas tank and gas line,and it did it again this year. Any ideas.Thanks
 
JB

JB

Honorary Moderator Emeritus
Joined
Mar 25, 2001
Messages
45,907
Re: 25 hp merc power problem

Howdy, Fishyman.<br /><br />Sounds like something in your ignition system has to warm up to work. <br /><br />With engine idling and cold, pull each plug wire in turn.<br /><br />If the engine dies, that cylinder is okay. If there is no change, check to see if you can get a hot, blue spark to the block. <br /><br />My guess is that you are not getting spark to one cylinder when cold. <br /><br />If I am right, try swapping coils, plugs, plug wires to see which one the trouble follows.<br /><br />Good luck. :)
 
M

MILLER TIME

Recruit
Joined
May 6, 2003
Messages
2
Re: 25 hp merc power problem

SOUNDS TO ME IF YOU'VE GOT A SPARK PROPLEM.I WOULD GET A IN-LINE SPARK TESTER ONE YOU CAN LEAVE ON THE WIRE AND CKECK SPARK WHILE YOUR RUNNING.IF NOT GET A PAIR OF INSULATED PLIERS AND REMOVE THE WIRE JUST ENOUGH TO HEAR IF IT SPARKS.ALSO TRY ANOTHER SET OF SPARK PLUGS I'VE SEEN NEW PLUGS NOT WORK.ANOTHER THING TO TRY IS SQUEEZING THE PRIMER BULB WHILE UNDERWAY TO RULE OUT A FUEL PUMP PROPLEM.START WITH THAT,IF IT IS A SPARK PROBLEM YOUR GOING TO NEED A SERVICE MANUAL AND A PEAK READING VOLT METER TO TROUBLE SHOOT THE IGNITION SYSTEM.GOOD LUCK
 
M

mjf

Recruit
Joined
May 11, 2003
Messages
2
Re: 25 hp merc power problem

Thanks for answering so fast. I'll try pulling the plug wires then troubleshoot . Its probably not fuel , I had the carb rebuilt last year and when its running I have squeezed the ball -did not help. Thanks again for the advice, now I just need time to work on it.
 
You must log in or register to reply here.
Top